﻿/*
 * RSA, a suite of routines for performing RSA public-key computations in JavaScript.
 * Copyright 1998-2005 David Shapiro.
 * Dave Shapiro
 * dave@ohdave.com 
 * changed by Fuchun, 2010-05-06
 * fcrpg2005@gmail.com
 */



	(function($w) {

		if (typeof $w.RSAUtils === 'undefined')
			var RSAUtils = $w.RSAUtils = {};

		var biRadixBase = 2;
		var biRadixBits = 16;
		var bitsPerDigit = biRadixBits;
		var biRadix = 1 << 16; // = 2^16 = 65536
		var biHalfRadix = biRadix >>> 1;
		var biRadixSquared = biRadix * biRadix;
		var maxDigitVal = biRadix - 1;
		var maxInteger = 9999999999999998;

		// maxDigits:
		// Change this to accommodate your largest number size. Use
		// setMaxDigits()
		// to change it!
		//
		// In general, if you're working with numbers of size N bits, you'll
		// need 2*N
		// bits of storage. Each digit holds 16 bits. So, a 1024-bit key will
		// need
		//
		// 1024 * 2 / 16 = 128 digits of storage.
		//
		var maxDigits;
		var ZERO_ARRAY;
		var bigZero, bigOne;

		var BigInt = $w.BigInt = function(flag) {
			if (typeof flag == "boolean" && flag == true) {
				this.digits = null;
			} else {
				this.digits = ZERO_ARRAY.slice(0);
			}
			this.isNeg = false;
		};

		RSAUtils.setMaxDigits = function(value) {
			maxDigits = value;
			ZERO_ARRAY = new Array(maxDigits);
			for ( var iza = 0; iza < ZERO_ARRAY.length; iza++)
				ZERO_ARRAY[iza] = 0;
			bigZero = new BigInt();
			bigOne = new BigInt();
			bigOne.digits[0] = 1;
		};
		RSAUtils.setMaxDigits(20);

		// The maximum number of digits in base 10 you can convert to an
		// integer without JavaScript throwing up on you.
		var dpl10 = 15;

		RSAUtils.biFromNumber = function(i) {
			var result = new BigInt();
			result.isNeg = i < 0;
			i = Math.abs(i);
			var j = 0;
			while (i > 0) {
				result.digits[j++] = i & maxDigitVal;
				i = Math.floor(i / biRadix);
			}
			return result;
		};

		// lr10 = 10 ^ dpl10
		var lr10 = RSAUtils.biFromNumber(1000000000000000);

		RSAUtils.biFromDecimal = function(s) {
			var isNeg = s.charAt(0) == '-';
			var i = isNeg ? 1 : 0;
			var result;
			// Skip leading zeros.
			while (i < s.length && s.charAt(i) == '0')
				++i;
			if (i == s.length) {
				result = new BigInt();
			} else {
				var digitCount = s.length - i;
				var fgl = digitCount % dpl10;
				if (fgl == 0)
					fgl = dpl10;
				result = RSAUtils.biFromNumber(Number(s.substr(i, fgl)));
				i += fgl;
				while (i < s.length) {
					result = RSAUtils.biAdd(RSAUtils.biMultiply(result, lr10),
							RSAUtils.biFromNumber(Number(s.substr(i, dpl10))));
					i += dpl10;
				}
				result.isNeg = isNeg;
			}
			return result;
		};

		RSAUtils.biCopy = function(bi) {
			var result = new BigInt(true);
			result.digits = bi.digits.slice(0);
			result.isNeg = bi.isNeg;
			return result;
		};

		RSAUtils.reverseStr = function(s) {
			var result = "";
			for ( var i = s.length - 1; i > -1; --i) {
				result += s.charAt(i);
			}
			return result;
		};

		var hexatrigesimalToChar = [ '0', '1', '2', '3', '4', '5', '6', '7',
				'8', '9', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j',
				'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
				'w', 'x', 'y', 'z' ];

		RSAUtils.biToString = function(x, radix) { // 2 <= radix <= 36
			var b = new BigInt();
			b.digits[0] = radix;
			var qr = RSAUtils.biDivideModulo(x, b);
			var result = hexatrigesimalToChar[qr[1].digits[0]];
			while (RSAUtils.biCompare(qr[0], bigZero) == 1) {
				qr = RSAUtils.biDivideModulo(qr[0], b);
				digit = qr[1].digits[0];
				result += hexatrigesimalToChar[qr[1].digits[0]];
			}
			return (x.isNeg ? "-" : "") + RSAUtils.reverseStr(result);
		};

		RSAUtils.biToDecimal = function(x) {
			var b = new BigInt();
			b.digits[0] = 10;
			var qr = RSAUtils.biDivideModulo(x, b);
			var result = String(qr[1].digits[0]);
			while (RSAUtils.biCompare(qr[0], bigZero) == 1) {
				qr = RSAUtils.biDivideModulo(qr[0], b);
				result += String(qr[1].digits[0]);
			}
			return (x.isNeg ? "-" : "") + RSAUtils.reverseStr(result);
		};

		var hexToChar = [ '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
				'a', 'b', 'c', 'd', 'e', 'f' ];

		RSAUtils.digitToHex = function(n) {
			var mask = 0xf;
			var result = "";
			for (i = 0; i < 4; ++i) {
				result += hexToChar[n & mask];
				n >>>= 4;
			}
			return RSAUtils.reverseStr(result);
		};

		RSAUtils.biToHex = function(x) {
			var result = "";
			var n = RSAUtils.biHighIndex(x);
			for ( var i = RSAUtils.biHighIndex(x); i > -1; --i) {
				result += RSAUtils.digitToHex(x.digits[i]);
			}
			return result;
		};

		RSAUtils.charToHex = function(c) {
			var ZERO = 48;
			var NINE = ZERO + 9;
			var littleA = 97;
			var littleZ = littleA + 25;
			var bigA = 65;
			var bigZ = 65 + 25;
			var result;

			if (c >= ZERO && c <= NINE) {
				result = c - ZERO;
			} else if (c >= bigA && c <= bigZ) {
				result = 10 + c - bigA;
			} else if (c >= littleA && c <= littleZ) {
				result = 10 + c - littleA;
			} else {
				result = 0;
			}
			return result;
		};

		RSAUtils.hexToDigit = function(s) {
			var result = 0;
			var sl = Math.min(s.length, 4);
			for ( var i = 0; i < sl; ++i) {
				result <<= 4;
				result |= RSAUtils.charToHex(s.charCodeAt(i));
			}
			return result;
		};

		RSAUtils.biFromHex = function(s) {
			var result = new BigInt();
			var sl = s.length;
			for ( var i = sl, j = 0; i > 0; i -= 4, ++j) {
				result.digits[j] = RSAUtils.hexToDigit(s.substr(Math.max(i - 4,
						0), Math.min(i, 4)));
			}
			return result;
		};

		RSAUtils.biFromString = function(s, radix) {
			var isNeg = s.charAt(0) == '-';
			var istop = isNeg ? 1 : 0;
			var result = new BigInt();
			var place = new BigInt();
			place.digits[0] = 1; // radix^0
			for ( var i = s.length - 1; i >= istop; i--) {
				var c = s.charCodeAt(i);
				var digit = RSAUtils.charToHex(c);
				var biDigit = RSAUtils.biMultiplyDigit(place, digit);
				result = RSAUtils.biAdd(result, biDigit);
				place = RSAUtils.biMultiplyDigit(place, radix);
			}
			result.isNeg = isNeg;
			return result;
		};

		RSAUtils.biDump = function(b) {
			return (b.isNeg ? "-" : "") + b.digits.join(" ");
		};

		RSAUtils.biAdd = function(x, y) {
			var result;

			if (x.isNeg != y.isNeg) {
				y.isNeg = !y.isNeg;
				result = RSAUtils.biSubtract(x, y);
				y.isNeg = !y.isNeg;
			} else {
				result = new BigInt();
				var c = 0;
				var n;
				for ( var i = 0; i < x.digits.length; ++i) {
					n = x.digits[i] + y.digits[i] + c;
					result.digits[i] = n % biRadix;
					c = Number(n >= biRadix);
				}
				result.isNeg = x.isNeg;
			}
			return result;
		};

		RSAUtils.biSubtract = function(x, y) {
			var result;
			if (x.isNeg != y.isNeg) {
				y.isNeg = !y.isNeg;
				result = RSAUtils.biAdd(x, y);
				y.isNeg = !y.isNeg;
			} else {
				result = new BigInt();
				var n, c;
				c = 0;
				for ( var i = 0; i < x.digits.length; ++i) {
					n = x.digits[i] - y.digits[i] + c;
					result.digits[i] = n % biRadix;
					// Stupid non-conforming modulus operation.
					if (result.digits[i] < 0)
						result.digits[i] += biRadix;
					c = 0 - Number(n < 0);
				}
				// Fix up the negative sign, if any.
				if (c == -1) {
					c = 0;
					for ( var i = 0; i < x.digits.length; ++i) {
						n = 0 - result.digits[i] + c;
						result.digits[i] = n % biRadix;
						// Stupid non-conforming modulus operation.
						if (result.digits[i] < 0)
							result.digits[i] += biRadix;
						c = 0 - Number(n < 0);
					}
					// Result is opposite sign of arguments.
					result.isNeg = !x.isNeg;
				} else {
					// Result is same sign.
					result.isNeg = x.isNeg;
				}
			}
			return result;
		};

		RSAUtils.biHighIndex = function(x) {
			var result = x.digits.length - 1;
			while (result > 0 && x.digits[result] == 0)
				--result;
			return result;
		};

		RSAUtils.biNumBits = function(x) {
			var n = RSAUtils.biHighIndex(x);
			var d = x.digits[n];
			var m = (n + 1) * bitsPerDigit;
			var result;
			for (result = m; result > m - bitsPerDigit; --result) {
				if ((d & 0x8000) != 0)
					break;
				d <<= 1;
			}
			return result;
		};

		RSAUtils.biMultiply = function(x, y) {
			var result = new BigInt();
			var c;
			var n = RSAUtils.biHighIndex(x);
			var t = RSAUtils.biHighIndex(y);
			var u, uv, k;

			for ( var i = 0; i <= t; ++i) {
				c = 0;
				k = i;
				for (j = 0; j <= n; ++j, ++k) {
					uv = result.digits[k] + x.digits[j] * y.digits[i] + c;
					result.digits[k] = uv & maxDigitVal;
					c = uv >>> biRadixBits;
					// c = Math.floor(uv / biRadix);
				}
				result.digits[i + n + 1] = c;
			}
			// Someone give me a logical xor, please.
			result.isNeg = x.isNeg != y.isNeg;
			return result;
		};

		RSAUtils.biMultiplyDigit = function(x, y) {
			var n, c, uv;

			result = new BigInt();
			n = RSAUtils.biHighIndex(x);
			c = 0;
			for ( var j = 0; j <= n; ++j) {
				uv = result.digits[j] + x.digits[j] * y + c;
				result.digits[j] = uv & maxDigitVal;
				c = uv >>> biRadixBits;
				// c = Math.floor(uv / biRadix);
			}
			result.digits[1 + n] = c;
			return result;
		};

		RSAUtils.arrayCopy = function(src, srcStart, dest, destStart, n) {
			var m = Math.min(srcStart + n, src.length);
			for ( var i = srcStart, j = destStart; i < m; ++i, ++j) {
				dest[j] = src[i];
			}
		};

		var highBitMasks = [ 0x0000, 0x8000, 0xC000, 0xE000, 0xF000, 0xF800,
				0xFC00, 0xFE00, 0xFF00, 0xFF80, 0xFFC0, 0xFFE0, 0xFFF0, 0xFFF8,
				0xFFFC, 0xFFFE, 0xFFFF ];

		RSAUtils.biShiftLeft = function(x, n) {
			var digitCount = Math.floor(n / bitsPerDigit);
			var result = new BigInt();
			RSAUtils.arrayCopy(x.digits, 0, result.digits, digitCount,
					result.digits.length - digitCount);
			var bits = n % bitsPerDigit;
			var rightBits = bitsPerDigit - bits;
			for ( var i = result.digits.length - 1, i1 = i - 1; i > 0; --i, --i1) {
				result.digits[i] = ((result.digits[i] << bits) & maxDigitVal)
						| ((result.digits[i1] & highBitMasks[bits]) >>> (rightBits));
			}
			result.digits[0] = ((result.digits[i] << bits) & maxDigitVal);
			result.isNeg = x.isNeg;
			return result;
		};

		var lowBitMasks = [ 0x0000, 0x0001, 0x0003, 0x0007, 0x000F, 0x001F,
				0x003F, 0x007F, 0x00FF, 0x01FF, 0x03FF, 0x07FF, 0x0FFF, 0x1FFF,
				0x3FFF, 0x7FFF, 0xFFFF ];

		RSAUtils.biShiftRight = function(x, n) {
			var digitCount = Math.floor(n / bitsPerDigit);
			var result = new BigInt();
			RSAUtils.arrayCopy(x.digits, digitCount, result.digits, 0,
					x.digits.length - digitCount);
			var bits = n % bitsPerDigit;
			var leftBits = bitsPerDigit - bits;
			for ( var i = 0, i1 = i + 1; i < result.digits.length - 1; ++i, ++i1) {
				result.digits[i] = (result.digits[i] >>> bits)
						| ((result.digits[i1] & lowBitMasks[bits]) << leftBits);
			}
			result.digits[result.digits.length - 1] >>>= bits;
			result.isNeg = x.isNeg;
			return result;
		};

		RSAUtils.biMultiplyByRadixPower = function(x, n) {
			var result = new BigInt();
			RSAUtils.arrayCopy(x.digits, 0, result.digits, n,
					result.digits.length - n);
			return result;
		};

		RSAUtils.biDivideByRadixPower = function(x, n) {
			var result = new BigInt();
			RSAUtils.arrayCopy(x.digits, n, result.digits, 0,
					result.digits.length - n);
			return result;
		};

		RSAUtils.biModuloByRadixPower = function(x, n) {
			var result = new BigInt();
			RSAUtils.arrayCopy(x.digits, 0, result.digits, 0, n);
			return result;
		};

		RSAUtils.biCompare = function(x, y) {
			if (x.isNeg != y.isNeg) {
				return 1 - 2 * Number(x.isNeg);
			}
			for ( var i = x.digits.length - 1; i >= 0; --i) {
				if (x.digits[i] != y.digits[i]) {
					if (x.isNeg) {
						return 1 - 2 * Number(x.digits[i] > y.digits[i]);
					} else {
						return 1 - 2 * Number(x.digits[i] < y.digits[i]);
					}
				}
			}
			return 0;
		};

		RSAUtils.biDivideModulo = function(x, y) {
			var nb = RSAUtils.biNumBits(x);
			var tb = RSAUtils.biNumBits(y);
			var origYIsNeg = y.isNeg;
			var q, r;
			if (nb < tb) {
				// |x| < |y|
				if (x.isNeg) {
					q = RSAUtils.biCopy(bigOne);
					q.isNeg = !y.isNeg;
					x.isNeg = false;
					y.isNeg = false;
					r = biSubtract(y, x);
					// Restore signs, 'cause they're references.
					x.isNeg = true;
					y.isNeg = origYIsNeg;
				} else {
					q = new BigInt();
					r = RSAUtils.biCopy(x);
				}
				return [ q, r ];
			}

			q = new BigInt();
			r = x;

			// Normalize Y.
			var t = Math.ceil(tb / bitsPerDigit) - 1;
			var lambda = 0;
			while (y.digits[t] < biHalfRadix) {
				y = RSAUtils.biShiftLeft(y, 1);
				++lambda;
				++tb;
				t = Math.ceil(tb / bitsPerDigit) - 1;
			}
			// Shift r over to keep the quotient constant. We'll shift the
			// remainder back at the end.
			r = RSAUtils.biShiftLeft(r, lambda);
			nb += lambda; // Update the bit count for x.
			var n = Math.ceil(nb / bitsPerDigit) - 1;

			var b = RSAUtils.biMultiplyByRadixPower(y, n - t);
			while (RSAUtils.biCompare(r, b) != -1) {
				++q.digits[n - t];
				r = RSAUtils.biSubtract(r, b);
			}
			for ( var i = n; i > t; --i) {
				var ri = (i >= r.digits.length) ? 0 : r.digits[i];
				var ri1 = (i - 1 >= r.digits.length) ? 0 : r.digits[i - 1];
				var ri2 = (i - 2 >= r.digits.length) ? 0 : r.digits[i - 2];
				var yt = (t >= y.digits.length) ? 0 : y.digits[t];
				var yt1 = (t - 1 >= y.digits.length) ? 0 : y.digits[t - 1];
				if (ri == yt) {
					q.digits[i - t - 1] = maxDigitVal;
				} else {
					q.digits[i - t - 1] = Math.floor((ri * biRadix + ri1) / yt);
				}

				var c1 = q.digits[i - t - 1] * ((yt * biRadix) + yt1);
				var c2 = (ri * biRadixSquared) + ((ri1 * biRadix) + ri2);
				while (c1 > c2) {
					--q.digits[i - t - 1];
					c1 = q.digits[i - t - 1] * ((yt * biRadix) | yt1);
					c2 = (ri * biRadix * biRadix) + ((ri1 * biRadix) + ri2);
				}

				b = RSAUtils.biMultiplyByRadixPower(y, i - t - 1);
				r = RSAUtils.biSubtract(r, RSAUtils.biMultiplyDigit(b,
						q.digits[i - t - 1]));
				if (r.isNeg) {
					r = RSAUtils.biAdd(r, b);
					--q.digits[i - t - 1];
				}
			}
			r = RSAUtils.biShiftRight(r, lambda);
			// Fiddle with the signs and stuff to make sure that 0 <= r < y.
			q.isNeg = x.isNeg != origYIsNeg;
			if (x.isNeg) {
				if (origYIsNeg) {
					q = RSAUtils.biAdd(q, bigOne);
				} else {
					q = RSAUtils.biSubtract(q, bigOne);
				}
				y = RSAUtils.biShiftRight(y, lambda);
				r = RSAUtils.biSubtract(y, r);
			}
			// Check for the unbelievably stupid degenerate case of r == -0.
			if (r.digits[0] == 0 && RSAUtils.biHighIndex(r) == 0)
				r.isNeg = false;

			return [ q, r ];
		};

		RSAUtils.biDivide = function(x, y) {
			return RSAUtils.biDivideModulo(x, y)[0];
		};

		RSAUtils.biModulo = function(x, y) {
			return RSAUtils.biDivideModulo(x, y)[1];
		};

		RSAUtils.biMultiplyMod = function(x, y, m) {
			return RSAUtils.biModulo(RSAUtils.biMultiply(x, y), m);
		};

		RSAUtils.biPow = function(x, y) {
			var result = bigOne;
			var a = x;
			while (true) {
				if ((y & 1) != 0)
					result = RSAUtils.biMultiply(result, a);
				y >>= 1;
				if (y == 0)
					break;
				a = RSAUtils.biMultiply(a, a);
			}
			return result;
		};

		RSAUtils.biPowMod = function(x, y, m) {
			var result = bigOne;
			var a = x;
			var k = y;
			while (true) {
				if ((k.digits[0] & 1) != 0)
					result = RSAUtils.biMultiplyMod(result, a, m);
				k = RSAUtils.biShiftRight(k, 1);
				if (k.digits[0] == 0 && RSAUtils.biHighIndex(k) == 0)
					break;
				a = RSAUtils.biMultiplyMod(a, a, m);
			}
			return result;
		};

		$w.BarrettMu = function(m) {
			this.modulus = RSAUtils.biCopy(m);
			this.k = RSAUtils.biHighIndex(this.modulus) + 1;
			var b2k = new BigInt();
			b2k.digits[2 * this.k] = 1; // b2k = b^(2k)
			this.mu = RSAUtils.biDivide(b2k, this.modulus);
			this.bkplus1 = new BigInt();
			this.bkplus1.digits[this.k + 1] = 1; // bkplus1 = b^(k+1)
			this.modulo = BarrettMu_modulo;
			this.multiplyMod = BarrettMu_multiplyMod;
			this.powMod = BarrettMu_powMod;
		};

		function BarrettMu_modulo(x) {
			var $dmath = RSAUtils;
			var q1 = $dmath.biDivideByRadixPower(x, this.k - 1);
			var q2 = $dmath.biMultiply(q1, this.mu);
			var q3 = $dmath.biDivideByRadixPower(q2, this.k + 1);
			var r1 = $dmath.biModuloByRadixPower(x, this.k + 1);
			var r2term = $dmath.biMultiply(q3, this.modulus);
			var r2 = $dmath.biModuloByRadixPower(r2term, this.k + 1);
			var r = $dmath.biSubtract(r1, r2);
			if (r.isNeg) {
				r = $dmath.biAdd(r, this.bkplus1);
			}
			var rgtem = $dmath.biCompare(r, this.modulus) >= 0;
			while (rgtem) {
				r = $dmath.biSubtract(r, this.modulus);
				rgtem = $dmath.biCompare(r, this.modulus) >= 0;
			}
			return r;
		}

		function BarrettMu_multiplyMod(x, y) {
			/*
			 * x = this.modulo(x); y = this.modulo(y);
			 */
			var xy = RSAUtils.biMultiply(x, y);
			return this.modulo(xy);
		}

		function BarrettMu_powMod(x, y) {
			var result = new BigInt();
			result.digits[0] = 1;
			var a = x;
			var k = y;
			while (true) {
				if ((k.digits[0] & 1) != 0)
					result = this.multiplyMod(result, a);
				k = RSAUtils.biShiftRight(k, 1);
				if (k.digits[0] == 0 && RSAUtils.biHighIndex(k) == 0)
					break;
				a = this.multiplyMod(a, a);
			}
			return result;
		}

		var RSAKeyPair = function(encryptionExponent, decryptionExponent,
				modulus) {
			var $dmath = RSAUtils;
			this.e = $dmath.biFromHex(encryptionExponent);
			this.d = $dmath.biFromHex(decryptionExponent);
			this.m = $dmath.biFromHex(modulus);
			// We can do two bytes per digit, so
			// chunkSize = 2 * (number of digits in modulus - 1).
			// Since biHighIndex returns the high index, not the number of
			// digits, 1 has
			// already been subtracted.
			this.chunkSize = 2 * $dmath.biHighIndex(this.m);
			this.radix = 16;
			this.barrett = new $w.BarrettMu(this.m);
		};

		RSAUtils.getKeyPair = function(encryptionExponent, decryptionExponent,
				modulus) {
			return new RSAKeyPair(encryptionExponent, decryptionExponent,
					modulus);
		};

		if (typeof $w.twoDigit === 'undefined') {
			$w.twoDigit = function(n) {
				return (n < 10 ? "0" : "") + String(n);
			};
		}

		// Altered by Rob Saunders (rob@robsaunders.net). New routine pads the
		// string after it has been converted to an array. This fixes an
		// incompatibility with Flash MX's ActionScript.
		RSAUtils.encryptedString = function(key, s) {
			var a = [];
			var sl = s.length;
			var i = 0;
			while (i < sl) {
				a[i] = s.charCodeAt(i);
				i++;
			}

			while (a.length % key.chunkSize != 0) {
				a[i++] = 0;
			}

			var al = a.length;
			var result = "";
			var j, k, block;
			for (i = 0; i < al; i += key.chunkSize) {
				block = new BigInt();
				j = 0;
				for (k = i; k < i + key.chunkSize; ++j) {
					block.digits[j] = a[k++];
					block.digits[j] += a[k++] << 8;
				}
				var crypt = key.barrett.powMod(block, key.e);
				var text = key.radix == 16 ? RSAUtils.biToHex(crypt) : RSAUtils
						.biToString(crypt, key.radix);
				result += text + " ";
			}
			return result.substring(0, result.length - 1); // Remove last
															// space.
		};

		RSAUtils.decryptedString = function(key, s) {
			var blocks = s.split(" ");
			var result = "";
			var i, j, block;
			for (i = 0; i < blocks.length; ++i) {
				var bi;
				if (key.radix == 16) {
					bi = RSAUtils.biFromHex(blocks[i]);
				} else {
					bi = RSAUtils.biFromString(blocks[i], key.radix);
				}
				block = key.barrett.powMod(bi, key.d);
				for (j = 0; j <= RSAUtils.biHighIndex(block); ++j) {
					result += String.fromCharCode(block.digits[j] & 255,
							block.digits[j] >> 8);
				}
			}
			// Remove trailing null, if any.
			if (result.charCodeAt(result.length - 1) == 0) {
				result = result.substring(0, result.length - 1);
			}
			return result;
		};

		RSAUtils.setMaxDigits(130);

	})(window);
